[Evaluation of the degree of mitral stenosis : reassessment of the M mode echocardiographic index].

Fifty consecutive patients (32 female and 18 male) with mitral stenosis aged 11 to 60 years underwent cardiac catheterisation and echocardiography to determine the value of M mode in assessing the degree of stenosis. Mitral stenosis was pure in 47 cases; isolated in 31 cases; associated with minimal aortic regurgitation in 11 cases, with mild mitral incompetence in 3 cases and with tricuspid incompetence in 5 cases (all patients underwent aortography and left ventriculography). Mitral valve surface area (MSA) calculated from the Gorlin formula correlated well with the anatomical mitral valve area (r = 0.88) in the 30 operated patients and enabled the patients to be divided into three subgroups : Group I : 36 patients with severe mitral stenosis; MS less than 1.3 cm2 including 29 with very severe stenosis : MS less than 1.0 cm2; Group II : 9 cases of moderate stenosis (1.3 cm2 less than MS less than or equal to 1.8 cm2), and Group III : 8 cases of mild mitral stenosis (MS greater than 1.8 cm2). The indices correlating with haemodynamic MSA were, in decreasing order of significance : EF slope of early diastolic closure of the anterior leaflet (r = 0.74); maximal EE' diastolic separation of the two leaflets (r = 0.57); the ratio of left atrium/aortic root dimensions (r = 0.39) and the Q-mitral closure interval (r = 0.31). The left atrial emptying index, the mitral valve closure index and changes in the rapid phase of left ventricular filling did not correlate with the degree of stenosis. An EF slope of less than 15 mm/sec had a sensitivity of 77% and a specificity of 93% and was a satisfactory method for distinguishing patients in Group I from those in Group II.(ABSTRACT TRUNCATED AT 250 WORDS)